The present invention relates generally to voltage conversion techniques and, more particularly, to switched capacitor voltage converters and methods for integrated circuit devices.
Power management has become a critical component for advanced computing architectures, including both high-end microprocessor systems and mobile electronic devices. However, existing on-chip solutions have limited success in simultaneously achieving high output current and high power conversion efficiency.
In particular, nominal power supply voltage (VDD) values for CMOS (complementary metal oxide semiconductor) technology have been gradually reduced over the past years due to performance and power scaling. In turn, maintaining efficiency in power delivery systems has become more difficult as VDD is scaled down. At VDD=1 Volt (V), the energy loss from an external power source to the circuits operated at VDD is significant. Since the power loss on the delivery grid is inversely proportional to the square of the voltage (V2), the efficiency issue on power delivery is further exacerbated for so-called “low” VDD circuits (e.g., about 300-500 millivolts (mV)).
Additionally, multiple supply voltages are required for logic circuits, SRAM, and embedded DRAM on the same IC chip. These voltages are generated using a linear series voltage regulator or an inductive buck converter. An on-chip linear regulator uses resistive elements to reduce the voltage and thus is not energy efficient. Traditionally, buck converters require discrete off-chip inductors to achieve high power conversion efficiency. However, due to the difficulty in integrating high quality inductors on silicon substrates, an on-chip integrated buck converter has poor power conversion efficiency.
Accordingly, it would be desirable to be able to provide improved voltage conversion systems for integrated circuit devices and systems having multiple voltage domains.